Chemistry Alkanes/Alkenes
Experiment: Comparing reactivities of alkanes and alkenes
Aim: To compare the reactivities of an alkane and an alkene with bromine water and a solution of potassium permanganate (KMnO4).
Equipment:
• 4 test tubes
• Test-tube rack
• 4 pipettes
Safety: safety glasses must be worn to prevent injury to the eyes. Ensure room is well ventilated whilst using the hydro carbons.
Method:
1. Place 1 ml of sample A (cyclohexane) into a test tube containing 4 mls of the bromine water solution. Record observations of any reaction.
2. Place 1 ml of sample A (cyclohexane) into a test tube containing 4 mls of the potassium permanganate solution. Record observations of any reaction.
3. Place 1 ml of sample B (cyclohexene) into a test tube containing 4 mls of the bromine water solution. Record observations of any reaction.
4. Place 1 ml of sample B (cyclohexene) into a test tube containing 4 mls of the potassium permanganate solution. Record observations of any reaction.
RESULTS
Sample Reaction with br2 water Reaction with acidified KMnO4 Hydrocarbon (alkane/alkene)
A No reaction, both liquids immiscible, br2 water kept its yellow colour No reaction, both liquids immiscible, KMnO4 solution kept its purple colour Alkane
B Both liquids reacted, causing 2 immiscible transparent liquids Both liquids reacted, causing the KMnO4 solution to change to a brownie red colour Alkene
Analysis:
The positive reaction in the experiment was the reaction between the alkene (cyclohexene) and both the bromine water and the potassium permanganate solution. Below is a balanced structural formula for the reaction between cyclohexene and the bromine
Aim: To compare the reactivities of an alkane and an alkene with bromine water and a solution of potassium permanganate (KMnO4).
Equipment:
• 4 test tubes
• Test-tube rack
• 4 pipettes
Safety: safety glasses must be worn to prevent injury to the eyes. Ensure room is well ventilated whilst using the hydro carbons.
Method:
1. Place 1 ml of sample A (cyclohexane) into a test tube containing 4 mls of the bromine water solution. Record observations of any reaction.
2. Place 1 ml of sample A (cyclohexane) into a test tube containing 4 mls of the potassium permanganate solution. Record observations of any reaction.
3. Place 1 ml of sample B (cyclohexene) into a test tube containing 4 mls of the bromine water solution. Record observations of any reaction.
4. Place 1 ml of sample B (cyclohexene) into a test tube containing 4 mls of the potassium permanganate solution. Record observations of any reaction.
RESULTS
Sample Reaction with br2 water Reaction with acidified KMnO4 Hydrocarbon (alkane/alkene)
A No reaction, both liquids immiscible, br2 water kept its yellow colour No reaction, both liquids immiscible, KMnO4 solution kept its purple colour Alkane
B Both liquids reacted, causing 2 immiscible transparent liquids Both liquids reacted, causing the KMnO4 solution to change to a brownie red colour Alkene
Analysis:
The positive reaction in the experiment was the reaction between the alkene (cyclohexene) and both the bromine water and the potassium permanganate solution. Below is a balanced structural formula for the reaction between cyclohexene and the bromine